1. Field of the Invention
The present invention provides a physiologically compatible conductive agent comprising (a) a long chain water-soluble ionic polymeric thickening agent selected from the group consisting of a copolymer of methyl vinyl ether and maleic anhydride, carboxy polymethylene polymer, and mixtures thereof, present in an amount from about 0.05 wt. % to about 10 wt. %; (b) an unbranched or branched alcohol having from 1 to about 4 carbon atoms present in an amount up to about 70 wt. %; and (c) the balance water. The present invention also provides a physiologically compatible conductive agent comprising long chain water-soluble ionic polymeric thickening agent selected from the group consisting of a copolymer of methyl vinyl ether and maleic anhydride, carboxy polymethylene polymer, and mixtures thereof, present in an amount from about 0.05 wt % to about 10 wt. %; (b) a surface tension reducing amount of a surfactant; and (c) the balance water. The present invention further provides methods for transmitting electrical or ultrasonic impulses to a surface in contact with a transducer with a conductivity gap by applying to the conductivity gap the novel physiologically compatible conductive agents. The present invention also provides methods for preparing the physiologically compatible conductive agents of the present invention.
2. Description of the Background
The application of electrical and ultrasonic energy in the form of impulses to stimulate or monitor the progress of medical therapy or physical rehabilitation are old and well known techniques. These techniques generally rely upon the use of a transducer applied to a surface, such as electrodes, for applying electrical impulses, or a sound transducer for applying ultrasonic impulses. The surface to which the transducer may be applied may be the skin of an animal or a human or the transducer may be applied to the surface of an article for non-destructive testing purposes.
During the application of electrical impulses to the skin of an animal or person, the amperage which is applied may vary and can produce undesirable differences in the muscular action generated by the electrical current. Since skin has electrical resistance, the currents generated by the electrodes may irritate the skin. Generally, it is necessary to cover the electrode with an adsorbent material or apply a conductive gel to the skin of the animal or human. Conductive gels which are commercially available have the disadvantage of tending to liquefy under the influence of the ingredients in perspiration, such as body salts, and in the veterinary field cannot always penetrate and activate the surface of animal skin because of the oily fur and skin in animals.
U.S. Pat. No. 4,002,221 discloses a method for transmitting electrical impulses to a surface in contact with a transducer with a conductivity gap comprising applying a transducer coupling agent to the conductivity gap.